@Override public void endWindow() { for (AverageAlertData data : alerts) { try { avgAlertOutputPort.emit(JsonUtils.toJson(data)); } catch (IOException e) { logger.warn("Exception while converting object to JSON", e); } } alerts.clear(); for (Map.Entry<MerchantKey, MutableDouble> entry : currentSMAMap.entrySet()) { MerchantKey key = entry.getKey(); MutableDouble currentSma = entry.getValue(); MutableDouble lastSma = lastSMAMap.get(key); if (lastSma == null) { lastSma = new MutableDouble(currentSma.doubleValue()); lastSMAMap.put(key, lastSma); } else { lastSma.setValue(currentSma.getValue()); } } }